Select all points inside a polygon to create a new matrix

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Martha 2014-3-31

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评论： Martha 2014-3-31

Hi, I have a point cloud matrix x,y and I want to create a new matrix with all the points that are inside a polygon to create a new matrix with all the points that are inside a polygon.

Thank you in advance, Martha

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Answer 1

Walter Roberson 2014-3-31

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Find the convex hull, and then you can use the vertices in poly2mask()

If you want the hull to be non-convex (e.g., to follow the points of a "star") then you have more difficulty in defining "inside".

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Martha 2014-3-31

Thank you Walter, Im going to try it now!

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Answer 2

Star Strider 2014-3-31

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Would the inpolygon function do what you want?

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Martha 2014-3-31

I try the inpolygon, but it return to me a matrix of the same size, only specifying with 1 and 0 the points that are in or out. But I want a new matrix with only the elements that are inside the polygon

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